Multilateral well technology allows an operator to drill a parent wellbore, and subsequently drill a lateral wellbore that extends from the parent wellbore at a desired orientation and to a chosen depth. Generally, to drill a multilateral well, the parent wellbore is first drilled and then at least partially lined with a string of casing. The casing is subsequently cemented into the wellbore by circulating a cement slurry into the annular region formed between the casing and the surrounding wellbore wall. The combination of cement and casing strengthens the parent wellbore and facilitates the isolation of certain areas of the formation behind the casing for the production of hydrocarbons to an above ground location at the earth's surface where hydrocarbon production equipment is located.
To connect the parent wellbore to a lateral wellbore a casing exit (alternately referred to as a “window”) is created in the casing of the parent wellbore. The window can be formed by positioning a whipstock at a predetermined location in the parent wellbore. The whipstock is then used to deflect one or more mills laterally relative to the casing string and thereby penetrate part of the casing to form the window. A drill bit can be subsequently inserted through the window in order to drill the lateral wellbore to a desired depth, and the lateral wellbore can then be completed as desired.
Part of the completion process for the lateral wellbore often includes a hydraulic fracturing operation to help enhance hydrocarbon recovery from formations surrounding the lateral wellbore. One method to fracture the lateral wellbore includes running and deflecting a completion assembly into the lateral wellbore, securing the completion assembly in the lateral wellbore, and opening one or more sliding sleeves to expose flow ports that provide fluid communication between the completion assembly and the surrounding formation. A fluid is then injected under pressure into the surrounding formation via the exposed flow ports to hydraulically fracture the formation and thereby create a fluid-porous network in the formation whereby hydrocarbons can be extracted.
Currently, hydraulic fracturing operations in multilateral wells could require as many as eighteen separate runs into the well, plus any additional runs required to perform conventional plug and perforation operations. As can be appreciated, reducing the number of trips into the well can save a significant amount of time and expense.